Rotary drying machine



July 6, 1926. 1,591,053

J. A. REAVELL ROTARY DRYING MACHINE Filed NOV. 12-. 1925 I5 Sheets-Sheet 1 July 6,1926. I 1,591,053 J. A. REAVELL v EOTARY DRYING MQCHINE Filed Nov. 12. 1923 3 Sheets-Sheet 2.

July 6; 1926. w 1,591,053

. '1 J. A. REAVELL ROTARY DRYING MACHINE Filed Nov. 12. 1923 3 Sheets-Sheet 5 If/orgy/ Patented July 6, i926.

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f ROTARY Darius MACHINE. I

Application filed November 12,1923; Serial No;

In rotarysteam dryers previously: em

ployed, it has been customary *to immerse the drying rollers within a bath of the liquid material tobe dried. This has many disadvantages. become clogged and special scraping arrangements have to be provided for the purpose of removing the solidified-material, :A second difiiculty is encountered by the liquid [in the bath reaching" a" -temperature 1 due to contact with the drum which causes the liquor to boilfand ultimately to coagulate. In another type of drier in which a film of liquid is introduced between two: rollers i i p e to'the space beneath the'dr um. The ends of the trough areconstructed sol asi toengage closely-the cylindrical surface of the drum;

.'there is the difficulty of maintaining a con stant feed and the furthernecessit-y of havingduplicate scrapers and conveyors toltake the scrapedmaterial away.-

. Accordingto the present invention a drying machine, is provided comprising a rotary.-

drum and a feed trough arrangedvalongone side of the drum insuch' a manner as-to delivjer'liquid to be "dried onto the face of-the drum the ends of the trough being preferends of the drum. Means are preferably provided for removing dried material ,in

relatively small pieces from the side of the trough and the dried material is removed preferably by a" number of independently adjustable scraper blades so mounted as to b'epres'sedinto operative engagement with the surface of the drum by their own resiliency. I

Reference will now be to the accom jpanying drawings which illustrate, byway of a drying machine,

shown In Figures olf-'3 to'va'cuum drying;

and

according to the invention and in which-:

674,305, and in Great B ritain 1ebr'uary 28, 1923.

PATENTOFFICE? hFigure 5* shows on a larger scale themethod'of mounting the scraper blades .Referring first to Figures 1-3 the machine comprises a drum 1 having hollow trunnions 2 at its ends adapted-to rotate in bearings mounted on a'fixedframework 4 one ofthe said trunnions'bein'g' connected by suitable "gearing with a prime mover. Through 'glands'5 in the outer ends of the trunnions Firstly, the ends of the drums are passed pipes 6 for the inlet and exhaust of a fluid medium for'heating the drum. A

"feed trough 7 is mounted in the framework iand disposed parallel to the axis of rotation of thevdrum but belowrthe horizontal plane of thesaid axis and theinner side'of the trough adjacent the drum is constituted by a spring steel blade 8- whichengages the drum throughout its length; and v prevents overflow of the substance under treatment especially with, those whose solid content. is f. f

liable' toc-settle out, or again with liquids. that will stratify it maybe necessary to em-' ploy an agitator This consists of a rotatably constructed to prevent overflow to the able shaft '9 passing throu h glands formed at the ends of the troughfand fitted-withbladesor: paddles 10 which may be adjust- V agitating shaft is v driven by "chain Q and sprocket gear 11 nion 2.:

'To remove dried material, from the sure face of the:drum'l scraping devices are arranged on the side} remote from the feed trough and comprise ainumber of thin blades or plates 12 secured by" set screws [13 -.to a' r bar l hextending from end. to end ofitheflr framework 4' at a pointbelow the horizontal plane oflth-e axis of the dr'um, the; blades 12 being slotted at 15 to allow adjustment relativelytothe bar 1 Each scraper blade 12 is provided'uith one or more backing plates 16 and both blades and plates are preferably formed of-stainless spring steel (seezFigure 5). In mounting these ele inents the edges of theblades are caused to .bear against the' undcr surface of the drum i 4 to an extent sufficient to cause the blades to be slightly curved thereby enabling them to maintain a positivepressure contact with the surface of the by mang r their own resilience. The blades 12 are tapered in form so that their operative portions overlap and are preferably arranged as shown in Figure 2 with alternate blades in advance or the remainder. The blades may be covered by a shield 17 the upper edge of which lies close to the surface of the drumand which is formed integral with or secu'red to a trough 18 into which the matter removed by the blades falls and in which is disposed a worm conveyor 19 mounted on a shaft 20 carried in bearings in the ends of the trough 18 and provided with a pulley 21 for independent operation. The shield 17 however, is not normally required but is only used for special materials. The trough 18 has an outlet 22 for dried material and may have jacket 28 for heating its contents when required, this jacket being connected by'a pipe 24 with the inlet pipe 6 by which fluid heating medium enters the apparatus, Whilst the inlet to both pipes is controlled by a cock 25'.

The operation of the apparatus above de scribed is as tollows:-

The solid matter in solution constituting the liquid to be dried is fed into the trough '7 from any definite source or the level of liquid in the troi'ighina'y be kept practically constant by the employment ofa float valve .inter posed 'between the trough and a main supply tank. Rotation of the drum 1. in a clockwise direction, Figure 3, causes a film ofliqu'id to adhere to thessur'ra ce' of the drum, the heat of which is regulated so that it is suflicient' to drive o'fitthe moisture in the film during apartial rotation. The

scraper blades 12 each detach the hot dried material, the one in advance or the other. so that if the material does not of its own accord break up into fine particles when dry,

the scraper blades themselves detach the [material in broken ribbons or as fine scrapings which may be easily crushed. The dried material thus detached by the scrapers is removed continuously by the conveyor 19 and discharged into suitable receptacles through the outlet 22. a

The apparatus shown in Figure 4: is designed for use in vacuum drying in cases where the material to be dried necessitates the'relnoval of abnormal quantities or mois- Lture or vapour. This apparatus is similar in general construction and operation to that shown in Figures 1 to 3 and similar reference numerals have been used to indicate corresponding parts. The apparatus is enclosed wholly within a casing 26 having a flanged outlet .27 for connection to a condenser of the surface or jet type, depending upon the requirements 0]": the installation, and to a vacuum pump. The casing 26 is provided with glazed sight holes 28 and a socket for the introduction o1 a reed pipe 29 arranged to admit the liquid to be treated to the outer compartment 30 or a feedtrough 31;which 'may be divided into two compartments by a partition32 having weirs 33 formed at int-ervals throughout itslength; At either or both ends of the trough 31 is. a notch 34L communicating with an overflow pipe 35. The material detached from the surface or the drum by the scraper blades, which are arranged as in Figures 1&3, is defiectedinto the conveyor trough by plates 36' and 37 and an apron '38 extending downwardly from the bar .14 on which the scraper blades are mounted ,The deflector plate 36 extends inwards nearly'to the surface of the drum and serves .to catch any material which is loosened, but falls ahead of the scraper blades and to deflect such material back into the conveyor trough 18. In this form of the invention the worm conveyor trough communicates with a vacuum box or boxes, preferably two beingemployed so that as one s filled the valve leading to it is closed, the valve to the. other box opened and the direction of movement of the conveyor reversed. In this manner one box can be emptied as the other is filled and the operation of the apparatus 1s continuous. In operatlon' serve to maintain a constant level o'fllquld in the inner compartment of the trough 31' so that the drying drum is suppliedcOntinuously with a uniform film ofliquid.

the partition and weirsl38 The devices above described are capable.

of considerable modification without departing from the invention For example,- the feed trough may be movably mounted and adapted to be raised or lowered against the decidinglevel of a float valve or supply .7

tank to regulate the feed of liquid tothe heated drum. blades may be arranged in various, relative positions other than those shown and any Furthermore, the scraper type of conveyor capable of moving the dried material longitudinallyo'f the trough 18 may be employed. I

I claim:+ 'e

1. In a drying machine, a rotary drum, a

feed trough for liquid material to be dried arranged along one side or said drum and having an upper edge engaging-said drum below the level of the other edgeofsaid trougln said drum forming a wall of said trough, and a plurality ofindependently ad justable staggered scraping. devices; fior blades and backing plates to said bar, said f blades being slotted to allow indepenclenitadj u stinent relatively to'the bar.

4.111 a drying inaehine'a rotary drumfa feed trough for: liquid to be dried arranged along one side of Said drum and having an upperledge engaging said drum below. the level of the other edge of said trough, said drum forming a wall of said trough, a bar fixed horizontally below the level of the axis of said drum, a pluralit of scraper blades andlbacking plates,'set screws seeniing said blades and backing plates tosaid bar", and slots in said blades for allowing independent adjustment of said blacles'relatively to said bait, said blades having staggered overlap} ping cutting-edges and being pressed into en- 7 JAMES ARTHUR nEA E L." Q 

